Among the common additives found in polymer compositions are colorants, such as pigments, and stabilizers, such as anti-oxidants and light stabilizers. Many commercial polymeric materials need stabilizers both for processing and long term aging, while pigments of course offer a full range of color options with good durability.
In order to obtain good color properties, as well as to prevent polymer processing problems, pigments are often treated or processed in some way prior to incorporation into a polymer system. Such pre-treatment of the pigment can, for example, provide better handling properties such as easier pigment flow or reduced pigment dusting and/or prevent the pigment from clumping together during processing to give better dispersion of the pigment in the polymer which can result in a higher color yield.
For Example, U.S. Pat. Nos. 7,033,429; 7,029,818; 6,596,073; 6,369,131 and 4,5055,439, all incorporated herein in their entirety by reference, disclose ways of preparing easily handled, low dust pigment preparations of organic and inorganic pigments. Frequently employed materials in such preparations include surfactants, wetting agents, waxes, polymer resins and the like.
However, one must be aware of the interactions between the components of a pigment formulation and the other additives found in the polymer system. Some of these interactions may have a negative impact not just on processing, but on the resulting color as well.
It has been found that the need for the aforementioned additives, i.e., surfactants, wetting agents, waxes, polymer resins etc, can be reduced or eliminated by the low dust pigment compositions of the present invention. These easily handled, high color yield compositions are readily formed in a straightforward manner by mixing pigments with certain polymer stabilizers under conditions wherein the stabilizers are in a liquefied state. In many cases, the color development attained is not readily achievable by conventional carriers.